1. Technical Field
This disclosure relates to an inkjet recording device for printing images on a printing medium by ejecting ink, and more particularly to a wiping device for eliminating fluid attached to the nozzle of the inkjet printer.
2. Description of the Related Art
An inkjet recording device is generally required to have a mechanism for maintaining the performance of the recording head that ejects ink droplets. As the functions of the mechanism, there are, for example, a capping function to prevent the nozzles ejecting ink droplets from dehydrating, a pumping function to fill the recording head with ink, and a nozzle cleaning function to clean the surface of the nozzle array of the recording head. Among those functions, the nozzle cleaning function is important, because when ejected ink droplets remain on the nozzle surface or foreign matter adheres to the nozzle surface, ink droplets may be ejected in the undesired direction or may become unable to be ejected, thereby seriously degrading the printing quality and image forming performance.
Furthermore, the speed of image forming processing has been increased in recent inkjet recording devices. To that end, throughputs improved by increasing the number of nozzles of the recording head so that more ink droplets can be ejected in a single scan. As a result, more ink droplets may be left behind on the nozzle surface and the remaining ink droplets are wiped off with a wiper blade. However, when the nozzle surface is wiped off by the wiper blade as described, there is a problem that the ink droplets wiped off from the nozzle surface and adhered to the wiper blade may be flicked off at the moment when the wiper blade is separated from the recording head after wiping the nozzle surface due to the elastic reaction of the wiper blade, thereby contaminating the inside of the printer body with the spattered ink droplets and degrading the printing quality.
To prevent the ink droplets adhered to the wiper blade from flicking off from the wiper blade, according to an inkjet recording device disclosed in the Patent Document 1 below, the wiper blade separates from the nozzle surface after passing the middle of the nozzle surface but before passing the end of the nozzle surface so that the wiper blade and the recording head are no longer in contact after the elastically deformed condition of the wiper blade is released.
Further, according to an inkjet recording device disclosed in the Patent Document 2 below, when the ink droplets left behind on the nozzle surface of the recording head are wiped with a wiper blade capable of moving in the direction vertical to the height direction of the nozzle surface of the recording head, a carriage on which the recording head is mounted while performing a round-trip scanning movement is stopped in the middle of wiping operations while the wiper blade is bent. Then the wiper blade is moved to wipe the remaining nozzle surface while the wiper blade is gradually being lowered so as to reduce the elastic deformation of the wiper bade, thereby reducing the amount of flicked ink droplets.
According to an inkjet recording device disclosed in the Patent Document 3 below, the wiper member for wiping off the nozzle surface of a recording head includes an ink absorbing section having elastic and superior water-absorbing characteristics and a wiping section provided adjacent to the ink absorbing section, closer to the nozzle surface than the ink absorbing section, and having lower water-absorbing characteristics. As a result, the wiping section wipes the ink droplets and the paper dust on the nozzle surface and then the wiped ink droplets and the like are absorbed into the ink absorbing section, thereby preventing the ink droplets from scattering.
Further, according to an inkjet recording device disclosed in the Patent Document 4 below, there is provided an escape surface on the downstream side of the recording head (on the side where the wiper blade separates from the recording head) such that the height direction of the recording head vertical to the nozzle surface is gradually reduced as the wiper blade approaches the end of the downstream side of the recording head. Because of this structure, when the wiper blade wiping the nozzle surface proceeds to wipe the escape surface, the elastic deformation of the wiper blade is gradually reduced, thereby preventing the remaining ink droplets on the header of the wiper blade from flicking off caused by the reaction force due to suddenly eliminating the elastic deformation of the wiper blade.
Patent Document 1: Japanese Patent Publication No: 3234087
Patent Document 2: Japanese Patent Application Publication No: 2006-192693
Patent Document 3: Japanese Patent Application Publication No: 2003-1833
Patent Document 4: Japanese Patent Application Publication No: 2002-79680
However, when the wiper blade separates from the nozzle surface after passing the middle of the nozzle surface but before passing the end of the nozzle surface as described in the Patent Document 1, or when the wiper blade gradually recedes from the nozzle surface during the wiping operations as described in the Patent Document 2, the portion between the middle to the end of the nozzle surface cannot be sufficiently wiped due to insufficient contacting pressure exerted by the wiper blade. As a result, the nozzle surface cannot be cleaned sufficiently and, disadvantageously, the ink droplets remaining on the nozzle surface due to the insufficient cleaning may contaminate recording paper.
Further, even when the wiper blade is arranged so that the wiping section having lower water-absorbing characteristics wipes the ink droplets and the paper dust on the nozzle surface, and then the wiped ink droplets and the like are absorbed into the ink absorbing section having superior water-absorbing characteristics as described in the Patent Document 3, the ink droplets may not be sufficiently absorbed into the ink absorbing section in a case where the paper dust adheres to the surface of the ink absorbing section.
Still further, the ink absorbing section is usually formed of an interconnected porous material so as to have water-absorbing characteristics. Since the holes of the porous material are likely to be sealed with a material such as the pigment of ink, the ink absorbing section may not stably absorb ink droplets for the long term. As a result, unfortunately, the scattering of ink droplets cannot be sufficiently prevented.
Further, since the wiper member includes an ink absorbing section having elastic and superior water-absorbing characteristics and a wiping section having lower water-absorbing characteristics, the structure of the wiper member is complicated, thereby complicating the forming process and increasing the cost of the wiper member.
Further, since the escape surface is formed on the downstream side of the nozzle surface to be wiped with the wiper blade as described in the Patent Document 4, the wiper blade cannot contact the escape surface with sufficient contact pressure. As a result, more ink droplets are likely to be left behind on the escape surface. In addition, if the left ink droplets are accumulated on the escape surface, the accumulated ink droplets may contaminate recording paper.